1. Field of the Invention
This invention relates to a connector for a catheter. More particularly, this invention relates to a connector for a catheter, capable of providing required connection between a catheter and a needle adopted in a method for injecting a medicinal liquid such as anesthetic through the catheter inserted into the blood vessel or epidural cavity, particularly the hollow needle method, with perfect ease of operation without fear of possible contamination, accidental separation or breakage of the portions held in connection by the connector.
2. Description of Prior Art
For the insertion of a catheter into the blood vessel, the hollow needle method or the cut-down method is available. The former method involves securing the blood vessel with a puncturing needle which consists of a stainless steel inner needle and a catheter assembly adapted to serve as an outer needle for incasing the inner needle, extracting the inner needle, inserting the catheter via the interior of the outer needle into the blood vessel to be indwelled therein, subsequently extracting the outer needle and removing it clearly of the outer end of the catheter, and fitting to the outer end of the catheter a connector possessed of a connecting needle. The latter method comprises surgically exposing the blood vessel from the patient's body, incising a cut in the exposed blood vessel, and inserting a catheter through the cut into the blood vessel to be indwelled therein. The catheter used in this method is provided integrally at the outer end thereof with a connector possessed of a connecting needle. The hollow needle method, therefore, is utilized extensively in the high-calorie transfusion therapy and the continuous epidural anesthesia.
A variety of connectors have heretofore been suggested for use on the outer end of the indwelling catheter to be inserted such as into the blood vessel in accordance with the hollow needle method. Among these connectors is counted, for example, a connector which comprises a hollow needle tube, a hub fitted round the outer surface of one end of the needle tube, and a cap attached to the rear end of the hub. This particular connector, however, is destined to collect dust in the portion where the needle tube and the catheter are joined to each other. When the indwelling of the catheter in the blood vessel is prolonged, therefore, there may arise the possibility that the blood will be contaminated by leakage through the portion of connection or the possibility that the needle tube will be fractured, the catheter bent at the leading end of the needle tube, and the connector accidentally separated or fractured.
Another connector for the indwelling catheter comprises a needle tube, a hub fitted round one end of the needle tube, a cap attached to the rear end of the hub, a protective tube detachably fitted round the hub and adapted to protect the needle tube and the catheter, a lower case detachably fitted round the hub and wrapped round the outer side of the protective tube to provide double protection, and an upper case detachably fitted round the lower case and adapted to protect the cap airtightly. The connector of this construction indeed is free from the posibility of the blood being contaminated by leakage through the portion of connection between the needle tube and the catheter and the possibility of the needle tube being fractured or the catheter being fractured at the leading portion of the needle tube. It nevertheless has a disadvantage that assemblage of all these components entails a complicate work. Specifically, the operation of the catheter using this particular connector is highly troublesome because it entails a procedure which involves the steps of passing the catheter through the lower case and the protective tube, joining the catheter and the needle tube to each other, then fitting the protective tube and the lower case round the hub in the order mentioned, removing the cap, attaching a syringe to the hub, injecting a medicinal liquid, subsequently replacing the cap, and setting the upper case in position.
Yet another connector for the indwelling catheter comprises a needle tube, a hub fitted round one end of the needle tube, a cap attached to the rear end of the hub, and a protective cylinder adapted to be passed through the catheter before the connection between the needle tube and the catheter and, after the connection therebetween, to have the rear end thereof fitted round the outer side of the hub and the other end thereof fastened so as to support the catheter in position (Utility Model Koaki Publication SHO-54(1979)-132,987). Similarly to the second connector cited above, this connector is free from the possibility of the blood being contaminated by leakage through the portion of connection between the needle tube and the catheter and the possibility of the needle tube being fractured or the catheter being bent and fractured at the forward end of the needle tube. It nevertheless has a disadvantage that was assemblage of this connector entails a complicate procedure comprising the steps of preparatorily separating the hub from the protective cylinder, fitting it round the catheter, connecting the catheter to the needle tube, and thereafter fitting the protective tube round the hub. It is also liable to expose the blood to contamination by leakage through the cap's side.
It is, therefore, an object of this invention to provide a novel connector for a catheter.
Another object of this invention is to provide a connector for the catheter, which permits the needle tube and the catheter to be connected to each other simply and quickly, enables the cap to be doubly sealed tightly and, at the same time, precludes the possibility of contamination being caused by leakage through the portion of connection between the needle tube and the catheter and the possibility of the catheter being fractured at the portion of connection at the leading end of the needle tube.